What does this research mean for the field?

The original claim that Cu 2+ induces fluorescence quenching in the carbon-dot-based dual-emission nanohybrid is not reproducible and is called into question due to significant data anomalies. Novelty: ClaimNovelty.CONTRADICTORY. Consensus alignment: ConsensusAlignment.CHALLENGES_CONSENSUS.

What question did this study set out to answer?

The central aim is to evaluate the reproducibility of a prior study's findings regarding copper ion imaging using a fluorescent sensor.

March 10, 2026

Correspondence on “Carbon‐Dot‐Based Dual‐Emission Nanohybrid Produces a Ratiometric Fluorescent Sensor for in Vivo Imaging of Cellular Copper Ions”

Key Points

The central aim is to evaluate the reproducibility of a prior study's findings regarding copper ion imaging using a fluorescent sensor.
Executed rigorous replication of the original experimental protocol from Zhu et al.
Focused on synthesis procedures and fluorescence measurements.
Conducted detailed analyses for data anomalies.
Failed to replicate the fluorescence quenching effect previously attributed to Cu2+ ions.
Identified significant anomalies in the data, including spectral overlaps.
Raised concerns about the integrity and reliability of the original study's results.

Abstract

ABSTRACT The 2012 study by Zhu et al. (DOI: 10.1002/ange.201109089) reporting a hybrid nanosystem composed of carbon and CdSe/ZnS quantum dots functionalized with tris(pyridin‐2‐ylmethyl)ethane‐1,2‐diamine (CdSe@C‐TPEA) as ratiometric fluorescent sensors for intracellular copper imaging remains highly influential, with 499 citations to date (Web of Science, December 4, 2025). As part of the NanoBubbles replication project, we attempted to reproduce key experimental findings following detailed pre‐registered protocols. Despite strict adherence to the reported synthesis procedures, we failed to replicate the central claim of Cu 2+ ‐induced fluorescence quenching. Furthermore, our analysis reveals significant data anomalies in the original publication, including spectral overlaps with identical noise patterns inconsistent with independent measurements. These findings raise critical concerns regarding data integrity and reproducibility and cast significant doubt on the reliability of Zhu et al.’s reported results.

Bookmark

Correspondence on “Carbon‐Dot‐Based Dual‐Emission Nanohybrid Produces a Ratiometric Fluorescent Sensor for in Vivo Imaging of Cellular Copper Ions”

Key Points

Abstract

Cite This Study